A quick summary of the photometric data extracted from spectra is presented
in Fig. REF . The \(B\)  and \(V\)  data lie well on a 1:1 relation
with APASS mean data, the scatter being at least in part related to the
variability all objects display (as per column \(\Delta V\)  of
Table REF ). The difference in the \(B\)\(-\)\(V\)  colour
(indicative of the accuracy of the slope of fluxed spectra) between
APASS and spectra appears well distributed around 0.0 with a FWHM of about
0.1 mag. The most interesting panel of Fig. REF  is the last
one, showing the distribution of \(U\)\(-\)\(B\)  measured on spectra compared with
the distribution of \(U\)\(-\)\(B\)  for a hundred M giants of the Solar
neighborhood (suffering from negligible reddening) as measured by
[1]}. It is clear how, on average, the \(U\)\(-\)\(B\) 
colour of candidate acc-SySt is bluer that those of (supposedly)
single, normal M giants, supporting the notion that for a sizeable fraction
of them we have actually observed an excess in \(U\)  as coming from the
companion and the accretion disk. The acc-SySt scoring an "spc" in
Table REF  are those with an \(U\)\(-\)\(B\)  bluer than +0.4 in
Fig. REF , and "spc:" for those between +0.4 and +0.8.
